Surgical table

ABSTRACT

A surgical table including a control system for facilitating manipulation of the table top when a patient is a normal and a reversed position. The table includes moveable table top sections whereby the table may be reconfigured from a normal configuration for receiving a patient with the patient&#39;s head at a head end of the table to a reversed configuration with the patient&#39;s head located at the foot end of the table. The controller is adapted to sense the configuration of the table and automatically reverse selectable functions for movement of the table when the table is in the reverse configuration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to surgical tables, and more particularly,to a surgical table having an articulated table top and an actuatorsystem and controller for providing improved control in moving a patientto desired positions.

2. Description of Related Prior Art

Various surgical tables having articulated table tops have beendeveloped to meet the growing demand of surgical tables which may beused for a plurality of different operations. Among the functionsdesirable for a surgical table are the ability to raise and lower thepatient support surface, provide lateral tilting of the patient supportsurface to the left and right, provide a pivoting of a seat sectionindependently of a back section, provide pivoting of a leg sectionindependently of the seat section, movement of the patient supportsurface into the trendelenburg and reverse trendelenburg positions, andmovement of the patient support surface into the flex and reflexpositions.

Further, during many operations, the patient is reversed from the normalorientation on the table wherein the table is reconfigured with the headsection moved to the foot end and mounted to the end of the leg sectionwhereby the leg section supports the back of the patient and the backsection supports the legs of the patient. In prior art tables, acontroller is provided with a reverse button to accommodate the reverseposition of the patient such that the direction of movement of the tablewill be reversed from the direction of movement provided in the normalmode of operation. For example, in the normal mode of operation, pushingthe trendelenburg button will cause the table to move into a positionwith the head end down lower than the foot end, and in the reverse modeof operation, pushing the same button will cause the foot end of thetable to be positioned lower than the head end whereby a patientoriented in the reverse position will have his or her head positioneddownwardly. Similarly, pushing the reverse button on the prior artcontroller will cause the lateral tilt to be reversed wherein the leftor right tilt of the patient will occur with reference to an operatorstanding adjacent to the head of the patient. Such a control systemrequires that the operator be aware of which end of the table isdesignated as the head end or foot end in order to properly determinewhether the patient is in a normal or reverse position on the table.Thus, coordinating the controls for the table with the particularpatient orientation requires an additional step on the part of theoperator.

During certain surgical operations, it is desirable to move a portion ofthe patient wherein one section of the surgical table pivoted out ofalignment with another adjacent section of the table is moved into aneutral position aligned parallel to the adjacent table section. Forexample, in an operation with the patient oriented in a reverse positionwith the back of the patient resting on the leg section of the table andthe leg section pivoted upwardly from the seat section, it may bedesirable to move the leg section downwardly into alignment with theseat section without altering the position of the seat section relativeto a support member for supporting the table top. During a typicaloperation, this realignment of a portion of the table top is complicatedby the provision of a draping extending over the patient and downwardlyover the sides of the table such that the relative orientation of thetable top sections cannot be readily observed without lifting thedraping.

Accordingly, there is a need for an articulated surgical table having anactuator and control system which permits the table to be easilymanipulated to desired positions while minimizing the level of operatorinput required.

SUMMARY OF THE INVENTION

The present invention provides a surgical table including an articulatedtable top which facilitates orientation of a patient for differentsurgical operations.

In one aspect of the invention, a surgical table is provided comprisinga table top, a support for supporting the table top, an actuator formoving the table top relative to the support, and a controller havingselectable functions for energizing the actuator to move the table topin a normal mode of operation when the surgical table is in a firstconfiguration and having a reverse mode of operation for reversing theselectable functions in a second configuration of the surgical table.

In a further aspect of the invention, the table top comprises aplurality of sections for supporting a patient and movement of one ofthe sections relative to at least one other of the sections causes thesurgical table to be reconfigured into the second configuration.Preferably, the plurality of sections includes a back section, a headsection mountable to the back section in the first configuration, a seatsection connected to the back section and a leg section connected to theseat section. The head section defines a moveable section for the tablewherein the head section may be mounted to the leg section toreconfigure the surgical table for the second configuration thereof.

In a further aspect of the invention, the table is provided with sensorsincluding switches associated with apertures located at first and secondends of the table top. The head section is provided with pins forengaging within the apertures wherein the pins are operable to actuatethe switches whereby the controller is provided with a signal indicatingthe particular configuration for the surgical table.

In yet another aspect of the invention, a method for controllingarticulation of a surgical table is provided including the steps ofoperating a controller to energize an actuator for moving a top portionof the table in accordance with preselected functions in a normal modeof operation, reconfiguring the surgical table to cause the controllerto be automatically switched to a reverse mode of operation, andoperating the controller to energize the actuator in the reverse mode ofoperation wherein the preselected functions are reversed from the normalmode of operation.

In a further aspect of the invention, a surgical table is providedcomprising a table top, a support for supporting the table top, anactuator system for moving the table top relative to the support, acontroller having selectable functions for energizing the actuatorsystem to move the table top, and wherein the controller automaticallydeactivates the actuator system when a predetermined portion of thetable top reaches a neutral position. The neutral position correspondsto positioning of a section of the table top in alignment substantiallyparallel to an adjacent section of the table top. In accordance withthis aspect of the invention, a manually actuable switch is provided foractivating at least one of the selectable functions for moving thepredetermined portion of the table top to the neutral position. Theswitch further being operable for activating the selectable function formoving the predetermined portion of the table top away from the neutralposition. The selectable functions include lateral left and right tiltfunctions, trendelenburg and reverse trendelenburg functions, andfunctions controlling movement of a seat section and leg section for thetable.

In another aspect of the invention, a method for controllingarticulation of a surgery table is provided including the steps ofselecting a first function on a controller for energizing an actuatorsystem to move a portion of a table top for the surgical table in afirst direction, selecting a second function on the controller toenergize the actuator system for moving the portion of the table top ina second direction opposite the first direction, and wherein thecontroller automatically terminates movement of the portion of the tabletop in the second direction when the portion of the table top reaches aneutral position. The method of controlling articulation of the surgicaltable further includes the step of disengaging the second switch andagain engaging the second switch to continue movement of the portion ofthe table top past the neutral position in the second direction.

In yet a further aspect of the invention, a surgical table is providedcomprising an articulated table top including a back section, a seatsection and a leg section, the seat section being pivotably mountedrelative to the back section; a support for supporting the table top; asystem of actuators for moving the sections of the table top; acontroller for energizing the system of actuators, the controller havinga normal mode of operation and a reverse mode of operation; and thecontroller being operable to energize the system of actuators toconfigure the table in flex and reflex positions wherein a flex/reflexpoint in the normal mode of operation is located between the back andthe seat sections, and a flex/reflex point in the reverse mode ofoperation is located between the seat and the leg sections.

In another aspect of the invention, a support cushion is provided foruse with the surgical table wherein the support cushion includes anupper layer defined by a foam cushion and a lower layer defined by aflexible x-ray transparent sheet of material, the lower layer beingsufficiently rigid to form a support for continuously supporting theweight of a patient across a gap between adjacent sections of the table.The lower layer is preferably formed of polypropylene and is adapted toprovide a continuous bridge across the gap during a flex movement of thesurgical table.

In another aspect of the invention, a surgical table is providedcomprising a table top including at least a seat section and a legsection mounted to the seat section; a support for supporting the tabletop; an actuator for driving the leg section in pivotable movementrelative to the seat section from a raised position approximately 80°above a plane defined by the seat section to a lowered positionapproximately 105° below the plane; and wherein a force applied to theleg section during the pivotable movement varies and the force is amaximum when the leg section is at the raised position.

Therefore, it is an object of the present invention to provide asurgical table including a controller wherein control of the surgicaltable by an operator is facilitated.

It is a further object of the invention to provide such a surgical tablewherein the surgical table automatically accommodates reversepositioning of a patient.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the surgical table of the presentinvention;

FIG. 2 is a diagrammatic plan view of the surgical table;

FIG. 3 is a side elevational diagrammatic view of the surgical table ina trendelenburg position;

FIG. 4 is a side elevational diagrammatic view of the surgical table ina reverse trendelenburg position;

FIG. 5 is an end view diagrammatically showing a left lateral tilt ofthe surgical table;

FIG. 6 is an end view diagrammatically showing a right lateral tilt forthe surgical table;

FIG. 7 is a side elevational diagrammatic view illustrating seat up andseat down positions;

FIG. 8 is a side elevational diagrammatic view illustrating the maximumraised and lowered positions for the leg section;

FIG. 9 is a side elevational diagrammatic view illustrating a flexposition;

FIG. 10 is a side elevational diagrammatic view illustrating a reflexposition;

FIG. 11 is a top plan view illustrating a head section for the surgicaltable;

FIG. 12 is an end view of the pin end of the head section;

FIG. 13 is an end view of the pin end of the leg section;

FIG. 14 is an end view of the seat section showing the mounting pointsfor the leg section;

FIG. 15 is a side elevational diagrammatic view illustrating thesurgical table in a flex position during a reverse mode of operation;

FIG. 16 is a side elevational diagrammatic view illustrating thesurgical table in a reflex position during a reverse mode of operation;

FIG. 17 is a perspective view, partially cut away, of a patient supportcushion for use with the present surgical table;

FIG. 18 is a cross-sectional end view through the patient cushion ofFIG. 17;

FIG. 19 is a side elevational diagrammatic view illustrating one of theactuation mechanisms for the leg section of the surgical table;

FIG. 20 is a front view of a pendant controller for the surgical table;

FIG. 21 is a side elevational diagrammatic view illustrating a return toneutral function of the surgical table;

FIG. 22 is a hydraulic diagram illustrating the hydraulic system for usein the present invention;

FIG. 23 is a perspective view showing the surgical table in an extremeelevated position;

FIG. 24 is a perspective view showing the surgical table in an extremetrendelenburg position;

FIGS. 25-28 are cross-sectional elevational views illustrating alatching mechanism for latching the leg section to the seat section;

FIG. 29 is a perspective view of a side extender assembly for thesurgical table mounted to the table;

FIG. 30 is an exploded view of the side extender assembly of FIG. 29;

FIG. 31 is a side elevational view showing two side extender assembliesmounted to a portion of the surgical table; and

FIG. 32 is an end view of the side extender assembly mounted to aportion of the surgical table.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, the surgical table 10 of the presentinvention comprises a table top 12 formed of a plurality ofinterconnected articulated sections including a head section 14, a backsection 16, a seat section 18 and a leg section 20. The table top 12 issupported on a support 22 including a base 24, a support column 26extending upwardly from the base 24 and a support bridge 28 mounted tothe top of the support column 26 and rigidly supporting the back section16 of the table top 12.

The support column 26 is vertically extendable and includes telescopingsections 26a, 26b and 26c for providing upward and downward movement ofthe table top 12. The mechanism for providing the upward and downwardmovement of the support column 26 is conventional and known in the art.

The support bridge 28 is supported on the top of the column 26 formovement about a lateral tilt axis 30 and a longitudinal tilt axis 32(see FIG. 2). The bridge 28 is actuated for movement relative to thesupport column 26 by means of an actuator 34 causing the bridge andtable top 12 to undergo lateral tilt movement about the axis 30, and anactuator 36 for causing the bridge 28 and table top 12 to undergolongitudinal tilt movement, such as for trendelenburg positions, aboutthe axis 32. The actuation mechanism for moving the bridge 28 relativeto the column 26 is shown diagrammatically for illustrative purposesonly and may comprise any known mechanism for tilting a surgical tableabout two axes. For example, a mechanism similar to that disclosed inU.S. Pat. No. 4,148,472 to Rais, et al., incorporated herein byreference, may be satisfactory for use in the present surgical table.

The table top sections 14, 16, 18, 20 each include a frame supporting asupport plate, and a cushion is attached to the upper surface of thesupport plate to provide a cushioned surface for a patient. Further, thetable 10 is also designed as a cantilever structure with the backsection 16, seat section 18 and leg section 20 extending in laterallyspaced relation relative to the support column 26 to provide maximumclearance for performing x-ray procedures. Also, the section frameportions, including the back section engaging portions of the bridge 28,are located adjacent to the lateral edges of the table sections suchthat the central portions of the table sections are clear ofobstruction, such as metal frame members, for facilitating performingx-ray procedures.

As best seen in FIG. 2, the head section 14 is removably mounted to oneend of the back section 16 at pin mounting points 38 and 40. The seatsection 18 is pivotably connected to the other end of the back section16 at articulated pivot connection points 42 and 44. Actuators in theform of power cylinders 46 and 48 are mounted within the side frameportions of the back section 16 for actuating the seat section 18 inpivotable movement upwardly or downwardly relative to the back section16. The leg section 20 is removably mounted to the seat section 18 atpin mounting points 50 and 52 comprising pivotably mounted blocks whichare actuated for movement by leg actuator mechanisms 54 and 56. The legactuator mechanisms 54 and 56 will be described in greater detail below.

It should be noted that a gap 58 is defined between the back section 16and the seat section 18, and a further gap 60 including a perinealcutout is provided between the seat section 18 and the leg section 20.The gaps 58 and 60 are adapted to provide sufficient space for a kidneyriser to be incorporated into the table when necessary for particularoperations.

The surgical table 10 is provided with a pre-programmed controllerincluding a microprocessor 61 and a hand held pendant controller 62 (seeFIGS. 1, 3 and 20) for controlling movement of the table 10. Inaddition, as depicted in FIG. 3, a further controller or control panel63 similar to pendant controller 62 may be provided permanently mountedto a side of the table 10 wherein the control panel 63 is adapted tocontrol the table 10 independently of the microprocessor 63. Theprogrammed controller 61 is programmed to provide various selectedfunctions for the table 10, which functions may be selected by pressingdifferent buttons on a panel 64 of the pendant or panel mountedcontrollers 62, 63. For example, the control system may be turned on andfloor locks (not shown) mounted within the base 24 may be actuated bypressing button 66 (FIG. 20) on the panel 64 whereby the locks move intoposition in engagement with a floor or surface. The floor lock mechanismdescribed in U.S. patent application No. (Attorney Docket No. MID 173P2), assigned to the assignee of the present invention, may be used inconjunction with the present table, and the disclosure of this U.S.patent application is incorporated herein by reference.

Referring to FIG. 22, a hydraulic system for the present surgical table10 is illustrated diagrammatically. It should be understood that thecontrollers 62, 63 are each operable to control actuation of thehydraulic system in order to actuate the various portions of the table10 for movement. The hydraulic system includes a pump system 171comprising an oil reservoir 170 within which is located a first pump 172and a second pump 174 driven by respective first and second motors 176,178 preferably located outside of the oil reservoir 170. One of thepumps, for example the first pump 172, is the main pump for the surgicaltable 10, and the other pump, for example the second pump 174, is abackup pump for use if the main pump 172 should become inoperable. Thepumps 172, 174 are connected to a common output line 180 throughrespective check valves 182. 184. The output line 180 defines apressurized fluid supply for the various actuation cylinders used in thesurgical table 10, and a return line 180 is provided for returning oilto the reservoir 170.

In addition, control valves are provided for controlling the fluid flowthrough the hydraulic system. Specifically, control valve 186 isprovided for controlling the bridge tilting actuator 36, control valve188 is provided for controlling actuators 46 and 48 for moving the seatsection 18, control valve 190 is provided for controlling actuation ofthe leg actuator mechanisms 54 and 56, control valve 192 is provided forcontrolling actuation of the lateral tilt actuator 34, control valve 194is provided for controlling an actuator 196 for providing a verticalheight adjustment for the table and control valves 198, 200 are providedfor controlling actuation of floor lock actuators 202 and 204, as isdescribed further in the above-noted U.S. patent application No.(Attorney Docket No. MID 173 P2).

It should be noted that either of the controllers 62, 63 may be used toenergize the pump system 171 and the control valves 186, 188, 190, 192,194, 198, 200. Generally, the movements of the surgical table 10 will becontrolled by the pendant controller 62 operating the main pump, forexample the first pump 172. However, in the event that the pump 172should fail in some manner, the backup pump, for example second pump174, is available to run the system. It should be noted that the systemis configured such that when the main pump 172 becomes inoperable, thependant controller 62 is disabled to control the surgical table 10, suchthat an operator must use the control panel 63 mounted to the table 10in order to actuate the table for movement. Further, use of thecontroller 63 results in the second pump 174 being energized to providepressurized fluid to the hydraulic system. This arrangement ensures thatthe operator is aware of a malfunction in the pump system, as indicatedby the pendant controller 62 being rendered inoperable, such thatrepairs will be effected in a timely manner to the malfunctioning pumpto ensure that both pumps are operational.

FIGS. 3-10 illustrate various movements provided for the surgical table10 by the controllers 62 and 63 wherein the support plate and frameportions of the table top sections are illustrated diagrammatically toshow the different positions. The positions provided by the controllers62, 63 will be described with particular reference to the pendantcontroller 62 (see FIG. 20) and are as follows: button 68 provides atrendelenburg position, as shown in FIG. 3, with a head end 70 of thetable located lower than a foot end 72 of the table; button 74 providesa reverse trendelenburg position, as illustrated in FIG. 4; buttons 76and 78 control the support column 26 to provide raised and loweredpositions, respectively, of the table top 12; buttons 80 and 82 provideleft and right lateral tilt, as viewed from the head end 70 andillustrated in FIGS. 5 and 6, respectively; button 84 functions to movethe seat section 18 upwardly, as illustrated in solid lines in FIG. 7;button 86 functions to move the seat section downwardly, as illustratedin dotted lines in FIG. 7; buttons 88 and 90 function to provide leg upand leg down functions, as illustrated in FIG. 8 by solid and dottedlines, respectively; button 92 functions to provide a flex position forthe table, as illustrated in FIG. 9; button 94 functions to provide areflex position for the table, as illustrated in FIG. 10; and button 96functions to move all of the table top sections to a level position. Inaddition, an unlock button 98 is provided wherein simultaneouslypressing the button 98 and the button 66 causes the floor locks todisengage from the floor, and a button 100 is provided for switching thetable off after table positioning is completed, although the table willnormally automatically be disabled ten seconds after the last button onthe pendant controller 62 is depressed. When the table has been turnedoff, it is necessary to first press the enable button 66 beforeproceeding with a positioning operation.

Referring to FIG. 11, the head section 14 is illustrated removed fromthe table 10 and includes side rails 102, 104 for mounting accessories.The head section 14 also includes mounting pins 106 and 108 for mountingthe head section 14 to the pin mounting points 38 and 40 located on theback section 16 as well as to pin mounting points 50, 52 on the seatsection 18 and to pin mounting points 110 and 112 provided at the end ofthe leg section 20, as shown in FIG. 2.

Referring to FIG. 12, an end view of the head section 14 is shownwherein the pin 108 includes a flattened portion 114. Similarly, as seenin FIG. 13, the leg section 20 includes mounting pins 116 and 118wherein the pin 116 includes a flattened portion 120. It should be notedthat the pin 108 having the flattened portion 114 on the head section 14is located on an opposite side from the side of the leg section 20having the pin 116 with a flattened portion 120.

Referring to FIG. 14, the end of the seat section 18 for receivingmounting pins of either the head section 14 or the leg section 20 isshown and includes mounting pin apertures 122 and 124. Associated witheach of the apertures 122 and 124 are respective sensors or sensorswitches 126 and 128. The switches 126 and 128 each include a respectiveplunger 130 and 132 for extending into the apertures 122 and 124. Thus,if the head section 14 is attached to the seat section 18 with the pins106 and 108 extending into the apertures 122 and 124, respectively, thepin 106 will actuate the switch 126 while the flat portion 114 of thepin 108 will cause the switch 128 to remain unactuated. This will signalthe controller 61 for the surgical table 10 that the head section 14 isattached to the table at this particular location.

Alternatively, when the leg section 20 is attached to the seat section18, the switch 128 is actuated while the switch 126 remains unactuatedto signal the controller 61 that the leg section 20 is in position atthis particular location adjacent to the seat section 18. Similarswitches are provided at the pin mounting points 38 and 40 of the backsection 16, as well as at the mounting point 110 at the end of the legsection 20. Further, the seat section mounting points 50 and 52 includeelectrical connectors 134 and 136, respectively, extending from thecontroller 61 and adapted to engage connectors (not shown) on a sectionattached to the seat section, such as on the leg section 20, wherebyelectrical connections to a switch or switches associated with mountingpoints at a distal end of the attached section are provided.

It should be noted that the above description of the different movementsof the surgical table 10 in response to actuation of the buttons on thependant controller 62 was made with reference to a normal mode ofoperation wherein the head section 14 was connected to the back section16 such that the patient's head is positioned adjacent to the head end70 of the table 10. In a reverse mode of operation, the head section 14would be positioned with the pins 106 and 108 engaged within the pinmounting points 110 and 112, respectively, of the leg section 20, orwithin the mounting points 50, 52 of the seat section 18. A switchassociated with the mounting point 110 or 50 and 52 would signal thecontroller 61 that the head section 14 is mounted at the foot end of thetable. In response to this signal, the controller will automaticallyreverse the control movements for the table. For example, with the headsection 14 attached to the end of the leg section 20, pressing thetrendelenburg button 68 will cause the foot end of the table 72 to lowerto a position below that of the head end 70, and a reverse movement willoccur when the reverse trendelenburg button 74 is depressed. Similarly,pressing the left lateral tilt button 80 will cause the table to tilt tothe left as viewed from the foot end 72 of the table, and an oppositemovement will occur in response to depressing the right lateral tiltbutton 82. Similarly, a relocation of the articulation points forflex/reflex movements will occur, as is described further below.

In addition, it should be noted that certain procedures may require thatthe leg section 20 be attached to the mounting points, 38, 40 on theback section 16 and the head section 14 be attached to the mountingpoints 50, 52 on the seat section 18. The controller 61 is adapted tosense the particular locations of the leg and head sections 20 and 14via the system of sensors and reverse the control operationsaccordingly.

It should be noted that when the patient is reversed on the table, thepatient's back will then rest upon the leg section 20, the patient'sbuttocks will rest on the seat section 18 and the patient's lees willrest on the back section 16. For the purpose of clarity, in the reversemode of operation the back section 16 and leg section 20 will bereferenced with the same terminology as used with the patient in thenormal position, although the portions of the patient supported by thesections in the reverse mode of operation are reversed.

As seen in FIG. 20, the buttons on the pendant controller 62 areprovided with diagrammatic illustrations showing the movement resultingfrom depressing the particular button. The movement of the table in thenormal mode of operation is illustrated with a solid circle showing thelocation of the patient's head, and the movement of the table in thereverse mode of operation is illustrated showing the location of thepatient's head with an outline circle. Thus, it can be seen from theillustrations on the controller buttons that the various movements foreach of the selected functions are reversed from the normal mode ofoperation when the head section is moved to the foot end of the table.

Referring to FIGS. 15 and 16, the flex and reflex movements of the tableare illustrated with the table operating in the reverse mode ofoperation. In addition, support cushions 138, 140 and 142 are shownpositioned on top of the table top sections 16, 18, 20 and 14. It shouldbe noted that the flexure point 144 for the flex/reflex function of thetable in the reverse mode of operation is displaced from the flexurepoint 146 for the flex/reflex function of the surgery table in thenormal mode of operation, as seen in FIGS. 9 and 10. Specifically, inthe normal mode of operation, the flexure point 146 is located betweenthe back section 16 and the seat section 18, whereas in the reverse modeof operation, the flexure point 144 is located between the seat section18 and the leg section 20. This shift in the flexure point occursautomatically in response to the change in the mounting point of thehead section 14 from the head end 70 of the table to the foot end 72 ofthe table. This shift in the flexure point is necessary since thepatient's hip will be moved from the flexure point 146 to the flexurepoint 144 when the patient is reversed on the table, and the table isreconfigured to accommodate the patient in this position.

Referring to FIGS. 23 and 24, it can be seen that the present table isadapted to provide extreme positions for positioning a patient which arenot typically available with prior art surgical tables. Specifically,FIG. 23 shows a position of the present surgical table 10 wherein thetable 10 is configured in the reverse configuration with the bridge 28pivoted upwardly and the back section 18, leg section 20 and headsection 14 are oriented substantially parallel to the floor and tiltedlaterally to one side. Further, an additional patient support section16' may be attached to an end of the back section 18 and extendingoutwardly over the seat section 16 to provide further support for thepatient. In this orientation of the table, a patient will be placed onthe table in a reverse position at an increased height over that of thenormal level position shown in FIG. 1. This position facilitates chestsurgery, for example, wherein a surgeon may stand behind the table (asseen in FIG. 23) with the patient at approximately chest height relativeto the surgeon.

Referring to FIG. 24, the table 10 is shown in an extreme trendelenburgposition with the bridge 28 tilted downwardly to increase the verticalorientation of the table top 12. In this configuration, the additionalpatient support section 16' described above with regard to FIG. 23 mayalso be added to the end of the back section 18 in order to provide afurther patient support surface. This position for the table may proveimportant for surgical procedures involving obese patients wherein theadditional movement of the table top toward a vertical positionfacilitates the use of gravity to draw the organs of the patient in adesired direction. Thus, it should be apparent from FIGS. 23 and 24 thatthe present invention enables an operator to obtain extreme positions,such as extreme height or extreme vertical orientation, for positioninga patient. Further, it should be noted that the cantilever constructionof the present table facilitates obtaining such extreme positions.

Referring to FIGS. 17 and 18, the cushion 140 for supporting the patientis further illustrated and includes structure for continuouslysupporting the patient over the gaps which occur between adjacentsections of the table, for example the gaps located at 58 and 60. Thecushion 140 is preferably designed to extend over two sections of thetable and is formed with a soft foam upper layer 148 and a flexiblelower layer 150 which is sufficiently rigid to form a support forcontinuously supporting the weight of a patient across a gap 58, 60located between adjacent sections of the table. The lower layer ispreferably formed from an x-ray transparent sheet of material such aspolypropylene. Further, the lower layer of polypropylene is preferablyformed with a thickness of approximately 2 mm such that thepolypropylene layer is flexible while also sufficiently rigid to form abridge supporting a patient across the gap in the table. The upper layer148 and lower layer 150 are surrounded by an outer cover 152 wherein theouter layer 152 is formed of an upholstery material, such as vinyl. Ascan be seen in FIGS. 15 and 16, the provision of such a cushion isparticularly useful for providing a smooth continuous surface betweentable sections during flexure of the table top 12.

Referring to FIGS. 8 and 19, the leg section 20 of the present table isadapted to move between a raised position of 80° above a plane definedby the seat section 18 to a lowered position 105° below the planedefined by the seat section 18. The raised position is typically used inthe reverse mode of operation for supporting a patient substantiallyupright relative to the seat section 18, and the lowered position istypically used to move the leg section 20 out of the way during a normalmode of operation procedure such as one wherein access near the perinealcutout area of the table is required. During such movement of the legsection 20 it has been found that it is desirable to have the greatestavailable torque or force available for moving the leg section 20 whenthe leg section 20 is adjacent to its uppermost position, and the leastforce is required when the leg section is in its lowered position.Accordingly, the actuation mechanism 54 illustrated in FIG. 19 (which isidentical to the actuation mechanism 56) is designed to provide amaximum force when the leg section 20 is in its raised position and toprovide the least force when the leg section 20 is in the loweredposition.

The actuation mechanism 54 includes a slide 154 mounted for slidingmovement between a pair of facing slots 156 (one of which is shown)formed in the frame for the seat section 18. A linkage 158 is providedand includes a first end 160 connected to the mounting point block 50for connection to the leg section 20. It should be noted that themounting point 50 is defined as a block pivotably mounted to the seatsection 18 a pivot point 162. The linkage 158 includes a second end 164connected to the slide 154. It should be noted that the first and secondends 160 and 164 of the linkage 158 are pivotal at their connectionswith the mounting point block 50 and the slide 154, respectively. Theslots 156 define a linear path for the slide 154 wherein the pathdefined by the slots 156 advantageously extends downwardly in adirection toward the leg section 20. A driver in the form of a powercylinder, such as a fluid cylinder 166 is connected to the slide 154 fordriving the slide 154 along the path defined by the slots 156. It hasbeen found that by providing the particular drive connection illustratedin FIG. 19, that a maximum force is obtained when the leg section 20 isin its upper position and a minimum force is provided when it is in itslowered position such that an optimum compromise of varying forcesduring the movement of the leg section 20 is obtained.

In addition, it should be noted that the leg section 20 is formed as aunitary section such that the actuation mechanisms 54, 56 will cooperateto move the leg section 20. Further, to ensure that the force applied tothe leg section 20 is distributed uniformly between the mechanisms 54and 56, the fluid inlet side for one of the cylinders 166 for themechanisms 54, 56 is in fluid communication with the fluid outlet of theother cylinder 166, and vice-versa, as may be seen in FIG. 22. Thus, thefluid pressure driving the cylinders 166 is equalized between the twoactuation mechanisms 54 and 56.

Referring to FIGS. 20 and 21, the controller 61 for the present surgicaltable provides a further function which facilitates operator control ofthe table. During movement of any table section from a position out ofalignment with an adjacent section back toward parallel alignment withthe adjacent section, the controller 61 will cause the moving section toautomatically stop at a neutral position wherein the two sections arealigned parallel to each other. For example, as illustrated in FIG. 21,as the leg section 20 is moved upwardly in response to depressing thebutton 88 of the controller 62, the leg section 20 will move upwardly aslong as the button 88 is depressed, but only until it reaches theposition shown in dotted lines and designated 20'. When the leg section20 reaches the position 20', the controller will automatically terminateactuation of the actuator mechanisms 54 and 56. Movement of the legsection 20 may be continued by releasing and again depressing the button88. The means for monitoring the position of the different sections maybe provided in any conventional manner. For example, proximity sensorsmay be located on the cylinders for moving the different section, orseparate sensors for sensing the relative position of the sections maybe provided.

This return to neutral function provided by the controller 61 isconsidered to be an important feature for use in procedures wherein theoperator must move the surgical table top to a position where twoadjacent sections are aligned parallel to each other and wherein it isdifficult to observe the parallel alignment of the table sectionsbecause of surgical draping extending downwardly along the sides of thetable. Further, besides providing this function for the differentarticulated adjacent sections of the table, this function is alsoprovided for the lateral tilt function wherein movement of the table inthe lateral direction is terminated when the table reaches its levelposition in a lateral direction, and movement may be continued byreleasing and re-depressing the lateral tilt button.

In addition, it should be noted that the return to neutral positiondescribed above with reference to FIG. 21 is different from the functionprovided by the level button 96 in that the level button 96 returns allof the sections to a position where they are planer to each other andlevel relative to the base. In the return to neutral function, thesections are not necessarily moved to a level position, except for inthe lateral tilt direction, and individual sections may be moved intoalignment with adjacent sections without altering the positioning of theadjacent section.

The hand pendant controller 62 is provided with a display 168 wherebyinformation relating to the status of the table may be relayed to theoperator. The display 168 is an LCD display and may provide informationsuch as the mode of operation (normal/reverse), table function selected,status of the battery charge for powering the table and error messageswhich facilitate trouble shooting problems with the control system forthe table.

Referring to FIGS. 25-28, a particular latching mechanism for attachingthe leg section 20 to the seat section 18 is shown, and in particular anelevational cross-sectional view is shown through the aperture 122.Further, the latching mechanism is illustrated with reference to the pin106 being inserted into and captured within the aperture 122.

The latching mechanism includes a lever, depicted in phantom lines aselement 206 which is rotatably mounted to the side of the surgical table10. The lever 206 includes an oval cam member 208 which is eccentricallylocated relative to a center of rotation for the lever 206. The cam 208is engaged with a plunger assembly 210 having an upper shelf 212, alower shelf 214, and a recessed area 216 defined between the upper andlower shelves 212, 214 and into which the cam 208 extends. The lowershelf 214 is defined on a lower portion 218 of the plunger assembly 210and a coil compression spring 220 engages the lower portion 218 toprovide an upward biasing force against the plunger assembly 210.Similarly, the upper shelf 212 is defined on an upper portion 222 of theplunger assembly 210 and is engaged by a spring 224 which is smallerthan and exerts a lesser force than the spring 220.

The plunger assembly 210 further includes a latch pin 226 movable withinand extending through an upper wall 228 of the upper portion 222. Thelatch pin 226 is biased upwardly within the plunger assembly 210 by abelleville washer spring 230. In addition, the latch pin 226 is guidedin its vertical movement through the upper portion 222 by a guide shank232 extending upwardly through the upper portion 222.

As seen in FIG. 25, the latch pin 226 normally extends upwardly into theaperture 122 and the pin 106 includes a blunt nose portion 234 forcamming the latch pin 226 downwardly as the pin 106 is inserted into theaperture 122. As the latch pin 226 is cammed downwardly by the pin 106,the spring 220 will compress to permit downward movement of the plungerassembly 210. The pin 106 includes a slot 236 for receiving the latchpin 226 when the pin 106 is located in an engaged position within theaperture 122, as seen in FIG. 26. Thus, it should be apparent that thelatching mechanism of the present invention provides for automaticlatching of the pin 106 within the aperture 122 as it is insertedtherein to thereby prevent removal of the pin 106 from the aperture 122.

To further ensure that the pin 106 remains firmly located within theaperture 122, the lever 206 may be rotated upwardly to the positionshown in FIG. 27 whereby the cam 208 acts on the upper shelf 212 to pushthe plunger assembly 210 upwardly whereby the belleville washer spring230, as well as the spring 224, is compressed to provide a predeterminedcompressive force for moving the latch pin 226 upwardly into firmengagement with the pin 106. In this manner, the pin 106 is immovablylocked within the aperture 122 to positively position the leg section 20on the end of the seat section 18.

When it is desired to remove the pin 106 from the aperture 122, thelever 206 may be moved to the position shown in FIG. 28. In thisposition, the cam 208 acts on the lower shelf 214 to move the plungerassembly 210 downwardly against the force of the spring 220 whereby thelatch pin 226 is moved out of engagement with the slot 236. With anoperator thus holding the lever 206 in its downward position, the pin106 may be extracted from the aperture 122 to thereby separate the legsection 220 from the seat section 18. It should be understood that asimilar latch mechanism is provided for the opposite aperture 124 of theseat section 18 and operates in a manner similar to that describedabove.

In addition, it should be understood that the pin mounting points 38, 40on the back section 16 and 110, 112 on the leg section 20 may also beprovided with latching mechanisms similar to the latching mechanismdescribed above. In the preferred embodiment of the latching mechanismsfor the pin mounting points 38, 40 and 110, 112 the latching mechanismsdo not automatically latch the sections in place. Rather, they areformed similar to the above-described latching mechanism but without thespring 220 to bias the plunger assembly 210 upwardly such that thelatching mechanisms will operate to retain pins therein only by movementof an associated lever to the locking position shown in FIG. 27.Further, in such a latching mechanism, an additional movement of thelever is preferably provided to prevent inadvertent movement of thelever. For example, the lever may be provided with a lateral outwardmovement wherein the lever must be pulled outwardly before it may berotated.

It should be noted that by providing a removable leg section 20 thepresent surgical table 110 provides additional room for accommodatingthe C-arm of an x-ray apparatus and further provides sockets which maybe used for mounting additional accessories when the leg section 20 isnot in place. Examples of such accessories include attachments forshoulder arthroscopy, orthopedic extensions and split leg sections.

Referring to FIGS. 29-32, a side extender assembly 238 is shown forproviding additional width for the surgical table 210. The side extenderassembly is adapted to he used in conjunction with side rails, such asback section side rail 240 and seat section side rail 242 (FIG. 1), anda plurality of the extender assemblies 238 may be used located along thelength of the table 10, as seen in FIG. 3). Specifically, the sideextender assembly 238 may be mounted to a rail 242 for extending thewidth of the surgical table 10, as seen in FIG. 29.

Referring to FIG. 30, the extender assembly 238 includes a frame 244 forsupporting a cushion 246 wherein the frame is formed as a hollow memberhaving a passage 248 for receiving an x-ray panel therethrough. Itshould be noted that the table 10 of the present invention is providedwith elevated panels for supporting patient receiving cushions whereinx-ray panels may be passed between the frame of the table and thesupport panel, as may be seen for example at 14a, 16a, 18a and 20a inFIGS. 23 and 24.

The extender assembly 238 further includes support legs 250, 252defining rail receiving apertures 254, 256, respectively. As seen inFIG. 32, a tang 258, 260 defining an upper portion of the apertures 254,256 is adapted to extend over and behind the rail 242. Threaded studs262, 264 having tapered heads 263, 265 are provided extending throughthreaded apertures 266, 268 in the respective legs 250, 252. The studs262, 264 are each provided with a drop handle 270, 272 mounted to thestuds by pivot pins 274. As may be best seen in FIG. 32, the taperedheads 263, 265 of the studs 262, 264 are adapted to engage a lower rearedge of the rail 242 to thereby wedge the legs 250, 252 into firmengagement with the rail 242 in order to lock the side extender assembly238 against movement.

Further, thumb screws 276, 278 extend in threaded engagement laterallythrough the legs 250, 252, and each includes a pad 280, 282 on a distalend thereof for contacting a side portion of the table 10. Thus, afterthe studs 262, 264 have been tightened into engagement with the rail242, the thumb screws 276, 278 are turned into the legs 250, 252 tocause the pads 280, 282 to firmly engage the side of the table tothereby resist any moment forces which may tend to pivot the extenderassembly 238 relative to the rail 242.

In addition, it should be noted that the extender assembly 238 includesa side rail 284 mounted to the frame 244 by screws 286 and held in apredetermined spaced relation to the frame 244 by spacers 288. Thus,although the side extender assembly 238 of the present invention ismounted to one of the rails 240, 242 of the surgical table 10 such anarrangement does not eliminate the provision of a side rail for mountingaccessories to the table 10.

It should be apparent from the above description that the side extenderassembly 238 provided for the surgical table 10 of the present inventionis configured such that it permits use of the table in a manner similarto that when the extender assembly is not present. In particular, itpermits the use of x-ray panels which may be inserted through theextender assembly 238 as well as permitting the use of accessories to bemounted to the side rail 284 of the assembly 238.

Further, from the above description, it should be apparent that thepresent surgical table includes a control system for facilitatingoperator manipulation of the table. By providing a control system whichresponds to the particular configuration of the table, the possibilityof error or inconvenience introduced by requiring the operator tomanually input to the controller the particular mode of operation forthe table is minimized. In addition, it should be apparent that thepresent surgical table facilitates movement of the table sections byproviding a return to neutral function for the different selectablefunctions of the controller and by providing a mechanism formanipulating the leg section to optimize the forces required for eachposition of the leg section.

While the form of apparatus herein described constitutes a preferredembodiment of this invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:
 1. A surgical table comprising:a table top, saidtable top including a movable portion; a support for supporting saidtable top; an actuator for moving said table top relative to saidsupport; a controller having selectable functions for energizing saidactuator to move said table top to predetermined positions in a normalmode of operation when said surgical table is in a first configuration,and having a reverse mode of operation for reversing said selectablefunctions in a second configuration of said surgical table said movableportion of said table top being movable to reconfigure said surgicaltable from said first configuration to said second configuration; andincluding a sensor system located on said table for sensing engagementof said movable portion with said surgical table, and said selectablefunctions of said controller changing from said normal mode to saidreverse mode of operation in response to said sensor system sensingengagement and disengagement of said movable portion to and from saidtable top.
 2. The surgical table as recited in claim 1 wherein saidmovable portion of said table top comprises a patient support portion.3. The surgical table as recited in claim 1 wherein said table topcomprises a plurality of sections for supporting a patient, one of saidplurality of sections comprising said movable portion, and movement ofsaid movable portion relative to at least one other of said sectionscauses said surgical table to be reconfigured into said secondconfiguration.
 4. The surgical table as recited in claim 3 wherein saidplurality of sections includes a back section, a head section mountableto said back section in said first configuration, a seat sectionconnected to said back section and a leg section connected to said seatsection, said head section defining said movable portion and beingmountable to said leg section in said second configuration.
 5. Thesurgical table as recited in claim 4 wherein said sensor system isconnected to said controller for sensing the location of said headsection on said surgical table.
 6. The surgical table as recited inclaim 3 wherein said movable portion is attachable to said table top ata first location and a second location, said sensor system beingoperable to sense the location of said movable portion whereby saidcontroller is activated to reverse said selectable functions.
 7. Thesurgical table as recited in claim 1 wherein said sensor system includessensors located at opposing ends of said table and said movable portionof said table top is mountable to either of said opposing ends saidsensors being operable for sensing the location of said movable portionat either end of said table top.
 8. The surgical table as recited inclaim 7 wherein said selectable functions are reversed in response to asensed position of said movable portion of said table top being changed.9. The surgical table as recited in claim 1 wherein said selectablefunctions comprise trendelenburg, lateral tilt and flex movements forsaid table top.
 10. A surgical table comprising:an articulated table topincluding a plurality of interconnected sections; a system of actuatorsfor moving said sections; a controller having selectable functions forenergizing said actuator system to move said sections in a normal modeof operation and having a reverse mode of operation wherein saidselectable functions are reversed; wherein at least one of said sectionsis movable from a first position defining a first configuration to asecond position defining a second configuration on said surgical table,and movement of said at least one section from said first position tosaid second position causes said controller to operate in said reversemode of operation; and including sensors located at said first andsecond positions wherein said sensors are operable for sensing thelocation of said at least one section and for actuating said controllerto operate in either said normal or reverse mode of operation.
 11. Thesurgical table as recited in claim 10 wherein said at least one sectioncomprises a head section.
 12. The surgical table as recited in claim 10wherein said sensors include switches associated with apertures locatedat first and second ends of said table top corresponding to said firstand second positions, and said at least one section includes pins forengaging within said apertures, said pins being operable to actuate saidswitches.
 13. The surgical table as recited in claim 10 wherein at leasttwo of said sections are movably mounted to said surgical table, andsaid first and second positions are located at opposing ends of saidtable.
 14. The surgical table as recited in claim 13 wherein said atleast two sections comprise a head section and a leg section.
 15. Thesurgical table as recited in claim 10 wherein said plurality of sectionsincludes a back section, a head section mountable to said back sectionin said first configuration, a seat section connected to said backsection and a leg section mountable to said seat section, said headsection further being mountable to said leg section in said secondconfiguration.
 16. The surgical table as recited in claim 15 whereinsaid leg section is further mountable to said seat section at a locationopposite said back section.
 17. A surgical table comprising:a table top;a support for supporting said table top; an actuator system for movingsaid table top relative to said support; a controller including aplurality of function buttons which are manually operable and defineselectable functions for energizing said actuator system to move saidtable top; and wherein actuation of at least one of said functionbuttons energizes said actuator system to move a predetermined portionof said table top in a predetermined direction to a predeterminedneutral position where said controller automatically deactivates saidactuator system to terminate movement of said predetermined portion, andwherein release and further actuation of said at least one functionbutton energizes said actuation system to move said predeterminedportion in said predetermined direction past said neutral position. 18.The surgical table as recited in claim 17 wherein said table topcomprises a plurality of sections, said predetermined portion formingone of said sections, and said neutral position corresponds to saidpredetermined portion being aligned substantially parallel to anadjacent section.
 19. The surgical table as recited in claim 17 whereinsaid table top comprises a back section, a seat section and a legsection, said seat section being movable independently of said backsection and said leg section being movable independently of said seatsection.
 20. The surgical table as recited in claim 19 wherein saidpredetermined portion comprises said seat section and said neutralposition corresponds said seat section being aligned substantiallyparallel to said back section.
 21. The surgical table as recited inclaim 19 wherein said predetermined portion comprises said leg sectionand said neutral position corresponds to said leg section being alignedsubstantially parallel to said seat section.
 22. The surgical table asrecited in claim 17 wherein said selectable functions include lateralleft and right tilt functions and said neutral position corresponds tosaid table top being level in a lateral direction.
 23. The surgicaltable as recited in claim 17 wherein said selectable functions includetrendelenburg and reverse trendelenburg functions and said neutralposition corresponds to said table top being level in a longitudinaldirection.
 24. A surgical table comprising:an articulated table topincluding a plurality of interconnected sections mounted for pivotalmovement relative to each other; a support for supporting said tabletop; an actuator system for moving said sections; a controller includinga plurality of function buttons which are manually operable and defineselectable functions for energizing said actuator system to move saidsections; and wherein actuation of at least one of said function buttonsenergizes said actuator system to move at least one of said sections ina predetermined direction to a predetermined neutral position where saidcontroller automatically deactivates said actuator system to terminatemovement of said at least one section, and wherein release and furtheractuation of said at least one actuation button energizes said actuationsystem to move said at least one section in said predetermined directionpast said neutral position.
 25. The surgical table as recited in claim24 wherein said sections include a back section, a seat section adjacentto said back section, and a leg section adjacent to said seat section,said controller being operable for actuating said seat section formovement independently of said back section and for actuating said legsection for movement independently of said seat section.
 26. Thesurgical table as recited in claim 25 wherein movement of said seatsection is automatically terminated when said seat section issubstantially parallel to said back section and movement of said legsection is automatically terminated when said leg section issubstantially parallel to said seat section.
 27. A surgical tablecomprising:an articulated table top including a back section, a seatsection and a leg section, said seat section being pivotally mountedrelative to said back section and said leg section being pivotallymounted relative to said back section; a support for supporting saidtable top; a system of actuators for moving said sections of said tabletop; a controller for energizing said system of actuators, saidcontroller having a normal mode of operation and a reverse mode ofoperation; and said controller being operable to energize said system ofactuators to configure said table in flex and reflex positions wherein aflex/reflex point in said normal mode of operation is located betweensaid back and said seat sections and a flex/reflex point in said reversemode of operation is located between said seat and said leg sections.28. The surgical table as recited in claim 27 wherein said table top isadapted to be reconfigured and said controller automatically operates insaid reverse mode of operation in response to said table top beingreconfigured.
 29. The surgical table as recited in claim 28 wherein saidtable top includes a removable section adapted to be alternately locatedat a head end and a foot end of said table top said controllerautomatically operating in said reverse mode of operation in response tosaid removable section being mounted at said foot end of said table top.30. A surgical table comprising:a table top including at least a seatsection and a leg section mounted to said seat section; a support forsupporting said table top; an actuator for driving said leg section inpivotal movement relative to said seat section from a raised positionapproximately 80° above a plane defined by said seat section to alowered position approximately 105° below said plane; and wherein aforce applied to said leg section during said pivotal movement variessuch that forces applied by said actuator to said leg section to raiseand lower said leg section between the plane defined by the seat sectionand said raised position are greater than forces applied by saidactuator to said leg section to lower and raise said leg between theplane defined by the seat section and said lowered position.
 31. Thesurgical table as recited in claim 30 wherein said actuator includes aslide mounted for sliding movement along a predetermined path on saidseat section, a linkage having a first end connected to said leg sectionand a second end connected to said slide, and a driver for driving saidslide along said predetermined path.
 32. The surgical table as recitedin claim 31 wherein said predetermined path is linear.
 33. The surgicaltable as recited in claim 31 wherein said predetermined path extendsnon-parallel to said plane.
 34. The surgical table as recited in claim33 wherein said predetermined path extends downwardly in a directiontoward said leg section.
 35. The surgical table as recited in claim 31wherein said driver comprises a power cylinder.
 36. The surgical tableas recited in claim 35 including identical actuators located on opposingsides of said surgical table, each said actuator including a fluidcylinder and said fluid cylinders being connected in fluid communicationwith each other whereby said cylinders exert an equal actuation forcefor moving said leg section.
 37. The surgical table as recited in claim30 wherein said leg section is a unitary member spanning substantiallythe entire width of said surgical table, said leg section beingdetachable from said seat section.
 38. A surgical table comprising:atable top including at least a first section and a second sectiondetachably connected to said first section; a support for supportingsaid table top; a latch mechanism for retaining said second section inengagement with said first section, said latch mechanism automaticallylatching said second section onto said first section in response tomovement of said section into association with said first section; meansfor locking said latch mechanism to prevent removal of said secondsection from said first section; and wherein said second sectioncomprises an engagement pin and said first section comprises an aperturefor receiving said engagement pin, and said latch mechanism engages saidengagement pin to retain said second section on said first section. 39.The surgical table as recited in claim 38 wherein said latch mechanismincludes a latch pin resiliently biased into said aperture and saidengagement pin includes a slot for receiving said latch pin.
 40. Thesurgical table as recited in claim 39 wherein said latch mechanismincludes a plunger assembly movable relative to said aperture and saidlatch pin is supported for movement with said plunger assembly, saidlatch pin being further supported for movement within said plungerassembly.
 41. The surgical table as recited in claim 40 includingbiasing means within said plunger assembly for biasing said latch pin ina direction toward said aperture.
 42. The surgical table as recited inclaim 40 wherein said means for locking said latch mechanism comprises alever actuated cam member located in engagement with said plungerassembly for biasing said plunger assembly toward said aperture wherebysaid engagement pin is firmly locked within said aperture.
 43. Thesurgical table as recited in claim 42 wherein said lever is mounted forrotation and rotation of said lever in a first direction causes saidplunger assembly to move toward said aperture, and rotation of saidlever in a second opposite direction causes said plunger assembly tomove away from said aperture whereby said latch pin is moved out ofengagement with said slot.
 44. A surgical table comprising: a tabletop;a support for supporting said table top; an actuator for moving saidtable top relative to said support; control means for energizing saidactuator; a pump system for supplying pressurized fluid to saidactuator, said pump system comprising a first pump and a second pump;wherein said control means is operable to energize said first pump tosupply pressurized fluid to said actuator as long as said first pump isoperable, and said control means is operable to energize said secondpump in the event said first pump becomes inoperable; and wherein saidcontrol means comprises first and second controllers havingsubstantially identical function selection switches, said firstcontroller being operable to energize said first pump as long as saidfirst pump is operable, and only said second controller being operableto energize said second pump in the event said first pump becomesinoperable.
 45. The surgical table as recited in claim 44 wherein saidpump system includes first and second motors for driving said first andsecond pumps, respectively.
 46. The surgical table as recited in claim45 wherein said pump system includes a fluid reservoir containing saidfirst and second pumps, and said motors are located outside of saidreservoir.